Membrane proteins of normal red cells and platelets will be studied under various conditions of in vitro incubation utilizing the membrane label, diazotized I125-diiodosulfanilic acid, and chemical and electrophoretic techniques. The investigations will be extended to study these cells under the usual conditions of blood component storage and to the evaluation of effects of incubation on membrane proteins of red cells from patients with sickle cell disorders or hereditary spherocytosis. BIBLIOGRAPHIC REFERENCES: Sears D.A. and Friedman J.M.: Membrane binding of Heinz bodies produced in normal erythrocytes. Clin Res 23:49A, 1975. Presented at the 1975 annual meeting of the Southern Society for Clinical Investigation, New Orleans, La.; George J.N., Lewis P.C., and Sears D.A.: Symmetrical loss of membrane glycoproteins from circulating platelets. Clin Res 23:273A, 1975. Presented at the 1975 annual national meeting of the American Federation for Clinical Research, Atlantic City, N.J.